"I think it's pretty appalling," Dr. Chris Murray, the director of the institute, told ABC News. "I believe the United States is an exceptional country and we should be leading the world in improvements in health."

In 2007, life expectancy ranged among individual counties from 65.9 to 81.1 years for men and 73.5 and 86 years for women. Between 1987 and 2007, life expectancy increased nationwide from 71.3 years to 75.6 years for men and from 78.4 to 80.8 years for women. Despite the increase, Americans still lag more than three years behind the 10 longest-living nations, including Japan, Australia, Singapore and Sweden.

Women are not faring as well as men in increasing their life expectancy over time, according to the study.

"You have to realize that the gaps between smoking between men and women have gone away," Murray told ABC News. "The women are now, relative to men, smoking more. The obesity epidemic in women is greater than in men and in fact, progress in tackling blood pressures much worse in women than compared to men."

Dr. James Fang, a cardiologist at University Hospitals' Case Medical Center in Cleveland, is not surprised by the findings contained in the study.

"Women somehow still don't understand that they will be affected by heart disease … [it's] not on the radar screen," he told ABC News. "The health care profession may be guilty. We hammer [it] home for men [but are] not as aggressive for women."

Donna Bentley, his 62-year-old cardiac disease patient, is well educated and works hard on her risk factors.

"I do believe women put themselves last, especially if they have families. They need to think about what to eat, when to eat and [be strict about] exercise," she said to ABC News.

Dr. Fang said he believes there may also be another factor.

"Women are more stoic … they have a higher pain threshold than men. They don't usually say they are in pain." And therefore, may not be seeking treatment at the same rate as men.

In addition, ABC News found startling contrasts in life expectancy within the United States. In Virginia's Fairfax County, the average man lives to be 81 years old. However, in Mississippi's Holmes County a male usually only reaches the age of 65.

Women in Collier County, Florida have 12 years on those in Holmes County.

Even more surprising, some neighboring counties have wide differences. In Yuma County, Arizona the average life expectancy increased eight and a half years for men during the study's time period, but in neighboring La Paz County, it dropped by a year.

"When we look at both the trends in life expectancy and at what is happening in each county for the key drivers of life expectancy, we think that tobacco, the obesity epidemic and high levels of blood pressure are a key part of the explanation," said Murray.